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The binascii module contains a number of methods to convert between
binary and various ASCII-encoded binary representations. Normally, you will not
use these functions directly but use wrapper modules like uu,
base64, or binhex instead. The binascii module contains
low-level functions written in C for greater speed that are used by the
higher-level modules.

Note

a2b_* functions accept Unicode strings containing only ASCII characters.
Other functions only accept bytes-like objects (such as
bytes, bytearray and other objects that support the buffer
protocol).

Changed in version 3.3: ASCII-only unicode strings are now accepted by the a2b_* functions.

Convert binary data to a line of ASCII characters, the return value is the
converted line, including a newline char. The length of data should be at most
45. If backtick is true, zeros are represented by '`' instead of spaces.

Convert binary data to a line of ASCII characters in base64 coding. The return
value is the converted line, including a newline char if newline is
true. The output of this function conforms to RFC 3548.

Convert a block of quoted-printable data back to binary and return the binary
data. More than one line may be passed at a time. If the optional argument
header is present and true, underscores will be decoded as spaces.

Convert binary data to a line(s) of ASCII characters in quoted-printable
encoding. The return value is the converted line(s). If the optional argument
quotetabs is present and true, all tabs and spaces will be encoded. If the
optional argument istext is present and true, newlines are not encoded but
trailing whitespace will be encoded. If the optional argument header is
present and true, spaces will be encoded as underscores per RFC 1522. If the
optional argument header is present and false, newline characters will be
encoded as well; otherwise linefeed conversion might corrupt the binary data
stream.

Convert binhex4 formatted ASCII data to binary, without doing RLE-decompression.
The string should contain a complete number of binary bytes, or (in case of the
last portion of the binhex4 data) have the remaining bits zero.

Perform RLE-decompression on the data, as per the binhex4 standard. The
algorithm uses 0x90 after a byte as a repeat indicator, followed by a count.
A count of 0 specifies a byte value of 0x90. The routine returns the
decompressed data, unless data input data ends in an orphaned repeat indicator,
in which case the Incomplete exception is raised.

Changed in version 3.2: Accept only bytestring or bytearray objects as input.

Compute a 16-bit CRC value of data, starting with value as the
initial CRC, and return the result. This uses the CRC-CCITT polynomial
x16 + x12 + x5 + 1, often represented as
0x1021. This CRC is used in the binhex4 format.

Compute CRC-32, the 32-bit checksum of data, starting with an
initial CRC of value. The default initial CRC is zero. The algorithm
is consistent with the ZIP file checksum. Since the algorithm is designed for
use as a checksum algorithm, it is not suitable for use as a general hash
algorithm. Use as follows:

Return the hexadecimal representation of the binary data. Every byte of
data is converted into the corresponding 2-digit hex representation. The
returned bytes object is therefore twice as long as the length of data.

Return the binary data represented by the hexadecimal string hexstr. This
function is the inverse of b2a_hex(). hexstr must contain an even number
of hexadecimal digits (which can be upper or lower case), otherwise an
Error exception is raised.